Effects of Channel Thickness on Electrical Performance and Stability of High-Performance InSnO Thin-Film Transistors

InSnO (ITO) thin-film transistors (TFTs) attract much attention in fields of displays and low-cost integrated circuits (IC). In the present work, we demonstrate the high-performance, robust ITO TFTs that fabricated at process temperature no higher than 100 °C. The influences of channel thickness (tITO, respectively, 6, 9, 12, and 15 nm) on device performance and positive bias stress (PBS) stability of the ITO TFTs are examined. We found that content of oxygen defects positively correlates with tITO, leading to increases of both trap states as well as carrier concentration and synthetically determining electrical properties of the ITO TFTs. Interestingly, the ITO TFTs with a tITO of 9 nm exhibit the best performance and PBS stability, and typical electrical properties include a field-effect mobility (µFE) of 37.69 cm2/Vs, a Von of −2.3 V, a SS of 167.49 mV/decade, and an on–off current ratio over 107. This work paves the way for practical application of the ITO TFTs